The design of distributed data network topologies has been practiccd for many years. A distributed data communication network is a hierarchical system of hardware components arranged to connect each hardware device, directly or indirectly, to every other device. At the lowest level in the hierarchy are user terminals or host devices, which form part of the local access network. These terminals are linked to one or more concentrators, which are statistical multiplexers with several low data rate input data lines and fewer high data rate output data lines. The concentrators form the second level of the network hierarchy and, together with the terminals, form the local access network.
The concentrators, which may be connected to other concentrators in a hierarchical fashion, are ultimately connected to the backbone, which forms the highest level in the network hierarchy. The backbone consists of high data capacity lines that terminate at backbone nodes, the latter including one or more devices including a switching device for routing traffic within the backbone. Data traffic from the concentrators enters the backbone at the backbone nodes.
Systems for constructing the most efficient arrangement of nodes on the backbone have been so generic as not to accommodate all of the parameters typically used in the communications industry. Other approaches have been so narrowly focused so as to render the system relatively inflexible. The invention described herein overcomes the deficiencies with a unique system that permits greater facility for arriving at a particular node construction. Although certain assumptions are made with respect to local access cost and node capacity, the user is given great flexibility in varying many other parameters which control the node construction.